Flashcards in Epilepsy Deck (103):
What pathology causes mamillary body haemorrhage?
Volume loss in the hippocampus unilaterally. What is the diagnosis?
Mesial temporal sclerosis - loss of CA1 cells mainly
What is the classification of focal cortical dysplasia?
Blumcke et al
1 - Abnormal radial lamination arrest
2 - Abnormal longitudinal lamination arrest (seen on MRI as a white matter glial band)
3 - Associated with a primary / principle lesion
What is the name given to well defined abnormal periventricular grey matter within white matter?
What is the incidence of seizures?
4% of the population will have a seizure in their lifetime - 85% have normal imaging;
1% will go on to have epilepsy - 50% have normal imaging;
40% have refractory epilepsy - 20% have normal imaging;
What is the definition of epilepsy?
Recurrent unprovoked seizures
A seizure syndrome
What are the common pathologies causing refractory epilepsy?
Mesial temporal sclerosis, cortical development abn (FCD), tumour, caveroma and AVM
What results in mesial temporal sclerosis?
Linked to Febrile seizures as a child
What are the MRI features of mesial temporal sclerosis?
High FLAIR signal in the affected hippocampus with low volume on T1W images
Atrophy of the fornix and mamillary body due to Wallerian degeneration
Always look for another lesion! (present in 20%)
MTS can be bilateral so compare to the cingulum and insula for flair signal!
What is the semiology of a temporal lobe seizure?
Oral automatism, aura, deja vu
How many layers of cortex does the hippocampus have?
What are the stages of brain development?
Neuronal stem cell proliferation 7th week
Radial migration 8th week
Lamination into 6 layers
Abnormalities of this process are present in 25% of patients with intractable childhood epilepsy
What are the conditions that are caused by abnormal stem cell development?
What seizure malformations are due to abnormal migration?
Lissencephaly (anterior agyria = x chromosome and posterior agyria = Ch17)
Nodular / subependymal / band heterotopia
What are the seizure abnormalities with abnormal lamination?
Schizencephaly - open and closed lip (cleft is lined with polymicrogyria)
Epileptogenic tumours (DNET, gangliogliomas and PXA)
Vascular malformation / trauma
Ganglioglioma MRI features?
Partly cystic and calcified
MRI features of DNET?
Bubbly appearance high on FLAIR
No enhancement - (if you see it then they recur!)
Which phakomatoses causing abnormalities of cortical lamination?
Tuberous sclerosis and sturge weber
What proportion of epilepsy patients that are refractory to drugs?
What are the long term side effects of epilepsy in children?
Predisposed to accidents
Reduced number of jobs
Shortens life expectancy by 30% (SUDEP)
What are the indications for epilepsy surgery?
Drug resistance or catastrophic epilepsy of localized epilepsy type
What are the aims of epilepsy surgery?
Resect epileptogenic zone and a possible lesion or interrupt the spread of ictal activity
What does ictus mean?
Time of seizure
(Inter-ictal is between seizures)
What is drug resistant epilepsy?
Failure of 2 AED schedules to achieve seizure freedom
How would you work up an epilepsy patient?
History for semiology
EEG - ictal is better / Video EEG
(supplementary tests include:
Wada / PET / Ictal SPECT / fMRI)
What areas should be identified when evaluating a patient for seizure surgery?
Epileptogenic / ictal zone
Epileptogenic / ictal lesion
Functionally disturbed area
Seizure semiolgy area
What is the role of fMRI for seizure surgery?
If eloquent cortex overlaps the epileptogenic areas
What is the role of PET for pre-seizure surgery?
For evaluation of functional impairment
What are the indications for invasive evaluation (depth electrodes / implantable strips / grids) for epilepsy surgery?
Non-conclusive / discordant results from non-invasive
Overlap with eloquent brain
(used in 30% of cases)
How is the extent of resection determined for epilepsy surgery?
Based on ictal / inter-ictal EEG and MRI
What operations are performed for Epilepsy?
Temporal: AHE / ATL / Lesionectomy 40%
Extratemporal resections: Hemispherotomy / FCD resections / Callosotomy / Multiple subpial transsections / VNS 60%
How can epilepsy surgery be classified?
Resective / Disconnective / Palliative
What are the 3 types of temporal lobe epilepsy?
Whole lobe TLE / Mesial TLE and Lateral (neocortical TLE)
What structures are removed with a TLE
Anterior 2/3 of temporal lobe and AHC (4.5cm on left and 5.5 cm right from the tip)
What is a Spencer temporal lobectomy
Anterior 1/3 of the temporal lobe with AHC (Amygdala hippocampus complex)
What is the medial point of resection with a TLE?
A line from choroidal point to MCA in the sylvian fissure
What is different about an MRI for epilepsy surgery?
The plane of the axial image is taken through the hippocampus
What separates the dentate and parahippocampal gyrus?
What is the second most common cause of TLE?
Tumour (Mesial temporal sclerosis is no.1)
What are the extratemporal seizure procedures?
Frontal lobe lesionectomy / lobectomy
Multiple lesion / lobectomy
What are the diagnostic problems with extratemporal lobe epilepsy?
Seizure onset not focal
Interictal spikes not concordant with imaging
How can you treat seizures in eloquent cortex that cannot be resected?
Multiple subpial resections
What are the causes of extratemporal seizures?
Low grade astrocytomy
AVM / Cavernoma
What is the most common tumour causing extratemporal lobe epilepsy?
What are the indications for hemispherotomy?
Lateralising seizure activity towards a damaged hemisphere with already established deficit (hemiparesis / hemianopia)
What conditions require hemispherotomy for epilepsy?
What is the most successful type of epilepsy surgery?
What is Lennox-Gastaut?
What are the indications for callosotomy?
Refractory drop attacks
No MRI abnormality
No focal region of abnormality
**Callosotomy is being replaced by VNS in many centers
**Callosotomy gets rid of the drop attacks but other types of epilepsy many get worse
What is multiple subpial transections?
Multiple cuts through the superficial cortex every 5 mm
Palliative technique used in unresectable eloquent cortex
How is a success in palliative epilepsy surgery judged?
Reduction in seizure frequency by 50% - so complete seizure freedom is rare
What are the outcomes with VNS?
By 3 years 75% had a 50% reduction in seizure frequency. Note the efficacy increases with time.
What is targeted for seizure DBS?
Anterior nucleus of the thalamus (SANTE)
Depression rates go up post surgery
What is responsive cortical stimulators?
Implanted DBS electrode only fires when a seizure onset is detected
What is the difference in outcome between surgery and SRS for TLE?
Seizure outcome takes 12 months and are comparable to surgery but gamma knife has fewer cognitive deficits if dominant (verbal memory)
Which epilepsy surgery type has the lowest improvement in seizure frequency?
Callosotomy - as this prevents generalisation but does not reduce seizure frequency
Which cells are most vulnerable in febrile convulsions?
What are the features of disconnection syndrome?
Medical treatment for SEGA?
mTor pathway inhibitors (everolimus)
Genetics of Tuberous sclerosis?
Tsc1 & 2
Hamartin & Tuberin
What are all the possible brain abnormalities with Tuberous Sclerosis
What is SISCOM?
What are the important factors in taking an epilepsy history?
Semiology - seizure type
Frequency / onset
Drugs / duration
What tumours in the temporal lobe cause seizures?
Ganglioglioma / PXA / DNET / Cavernoma
Define subclinical seizure activity
What are the concerns with resecting a lesion causing epilepsy?
Resection of the lesion
Lesionectomy with rim (if cavernoma)
Resection of surrounding cortex which are found to be epileptogenic
What is ECOG?
Electrocorticography - can be used to monitor epileptiform activity and using SSEPs with phase reversal to identify the motor cortex (the area between the + and - is the central sulcus)
What are the vascular phakomatoses?
What is the relationship of the leptomeningeal enhancement to the portwine stain in sturge weber syndrome?
Posterior fossa CSF intensity cyst with small cerebellum?
Dandy walker malformation
What are the features of classical Dandy-walker malformation?
Inversion of torcula / lambdoid relationship
How can mega cisterna magna be differentiated from a posterior fossa arachnoid cyst?
Mega cisterna magna does not have mass effect on the cerebellum
What is the term to describe smooth flattened gyri?
What is kernicterus?
Features of hemi-megancephaly?
Enlarged cerebral and cerebellar hemisphere with enlarged ventricle
Polymicrogyria and subependymal grey matter heterotopia
Pachygyria (smoother and flattened gyri)
Most commonly frontal lobe is affected
Associate with ....(look it up!)
Child with retardation, infantile spasms and chorioretinal lacunes. MRI shows multiple intracranial cysts, callosal agenesis and optic nerve hypoplasia. Diagnosis?
Closed lip schizencephaly, lack of septum pellucidum with short stature?
What are the features of septo-optic dysplasia?
Absent septum pellucidum
Small optic chiasm
DD of a calcified suprasellar mass?
Meningioma - can have cystic types also
What occurs when the fetal white matter has hypoxic injury?
Why does the contralateral cerebellum reduce in size if there is a large fetal cortical stroke?
Cortico-cerebellar artrophy - Transsynaptic degeneration in the contralateral cerebellum due to corticopontine and ponto-cerebellar fibres (through the middle cerebellar peduncle)
What trials have been performed for gamma knife to TLE?
What is stereotactic laser hippocampectomy?
MR thermography used to monitor laser lesion
How does drug resistant epilepsy shorten your life?
What is the Engel classification?
1 Seizure free
2 Rare seizures
3 worthwhile Seizure reduction
4 not worthwhile
What is the psalterium?
Thinnest part between the fornix
What structure lies between the fornix and roof of 3rd nerve?
What is the main use of PET in Epilepsy?
Lateralisation by showing regions of functional impairment (interictal low uptake in the affect brain region)
What are the indications for invasive evaluation?
Overlap with eloquent cortex
What vessel is in the hippocampal fissure?
Anterior choroidal Artery
How is the MRI inclined for Epilepsy?
In the place of the hippocampus
Where is the hippocampal sulcus?
Between the dentate gyrus and parahippocampal gyrus
What is the best surgical technique for MTS?
Josephson et al systematic review showed better seizure outcome with ATL
What are the problems with extratemporal lobe epilepsy
Seizure onset often not focal
Interictal spikes are not concordant with imaging
What are the surgical options for ETL?
What are the main causes of ETL?
Low grade tumours (gangliogliomas most common)
What are the disconnection procedures?
How do you manage open lip schizencephaly?
What is the most successeful type of epilepsy surgery?
Why do you perform callosotomy?
Drop attacks (atonic, tonic clonic and Lennox Gestaut)
What is the side effect of callosotomy?
Increase in complex partial seizures
What are the palliative epilepsy procedures?